Fix code example to use @include instead of @import

Author: Matt

docs/components/block-grid.html.erb

@@ -75,7 +75,7 @@
 
 <%= code_example '
 /* Mixin and configurable options */
-.your-class-name { @import block-grid($per-row, $spacing, $base-styles); }
+.your-class-name { @include block-grid($per-row, $spacing, $base-styles); }
 
 /* This controls how many elements will be on each row of the block grid. */
 /* Set this to whatever number you need, up to the max allowed in the variable */